This invention relates to a paddle handle actuated door latch mechanism which is adapted to be mounted in a door such that the paddle handle is flush with the surface of the door.
In a flush mounted paddle handle actuated door latch, it is common to have the handle pivotally mounted within a recessed opening formed in a rectangular tray. A bolt is commonly mounted in a housing which is attached to the back of the tray. When the latch mechanism is operated, the bolt moves from an extended position, in which it passes through the eye of a striker plate when the door is closed, to a retracted position, in which the bolt is withdrawn from the eye. A problem with the aforementioned design is that the handle, which is located on one side of the tray, must connect to and operate the bolt which is mounted in the housing on the opposite side of the tray.
In one previous design, the bolt is operated by an actuating member on the handle which projects through an opening in the bottom of the tray and is received in an opening formed in the bolt. A problem with this design is that the actuating member is difficult to attach to the handle. If the member is formed as part of the handle it is necessary for the handle to be made out of a relatively thick piece of material. Such a piece of material is expensive and difficult to work with. Another problem with this design is that water can flow through the opening in the tray into the opening in the bolt and freeze to prevent operation of the latch mechanism.
In another latch mechanism, a paddle handle pivots a cam member which is mounted on the handle pivot pin and which projects through an opening in the tray and into an opening in the bolt; this slides the bolt from an extended position to a retracted position. This design eliminates the need for constructing the handle from a relatively thick piece of material. Disadvantages to the design include more complexity because of additional parts, and the vulnerability of the cam member and bolt to freezing.
Many paddle handle actuated latch mechanisms have a lock which prevents unauthorized operation of the mechanism. A common lock has a cylinder and a cam which engages the bolt or a member connected to the handle to prevent movement of the bolt or handle when the latch mechanism is locked. It is common to connect the cam to the lock cylinder by a screw or a rivet. In some instances, it is possible for an intruder to render the lock inoperative by applying a large force to the paddle handle. This force is transmitted to the lock cam to shear the screw or rivet which attaches the cam to the lock cylinder.
It is an object of the instant invention to provide a paddle handle actuated latch mechanism in which the connection between the paddle handle and the bolt does not require a portion of the handle to directly engage the bolt and is resistant to freezing.
It is a further object of the instant invention to provide a lock for a paddle handle actuated latch mechanism in which the lock cylinder cam is formed in such a way as to resist shearing of the means which attaches the cam to the lock cylinder.